December weather forecast and climate
Montana, USA

December is severely cold in Montana with the average high temperatures in the 25°F (-3.9°C) to 32°F (0°C) range and the average low temperatures in the freezing -1°F (-18.3°C) to 21°F (-6.1°C) range. The eastern half of the state is prone to cold weather with average low temperatures of 7°F (-13.9°C) in Glasgow and 8°F (-13.3°C) in Havre City, while the western half is comparatively warm with average low temperatures of 16°F (-8.9°C) in Kalispell and 21°F (-6.1°C) in Libby.
Snowfall is severe in the mountains and often crosses 50" (1270mm), while rain is mainly in the form of icy precipitation. The winter also brings a chilly wind that exacerbates the cooling effect, which the Chinook winds partially neutralize to keep the temperatures in check.
The average monthly sunshine is in the range of 45% to 50%, which means short days with a weak presence of the sun.
The intense cold mandates warm winter coats, caps, gloves, and boots during Christmas and New Year's Eve, whose celebrations mostly occur in the white blanket of snow!.